Multi Component Moulding
Multi component moulding is a common way of forming products that require characteristics, one material alone just cannot provide. It’s often used to give stability, functionality, product differentiation, added aesthetic appeal or marketability over traditional designs.
For example using a hard-soft component, the hard component provides the strength whereas the soft component acts as a sealant or insulation or generates good haptics. In most cases, the main purpose of combining the plastics in an injection moulding process is to save costs by reducing the number of processing, handling and assembly steps or joining processes.
In most applications, a good adhesion between the components is desired. It can be achieved by various means or a combination of methods listed below:
• Choosing the materials that are compatible with each other
• Modifying one component to improve compatibility with the second one
• Choosing materials that have similar surface energies
• Use of mechanical interlocks. A component is designed to flow around the injected component.
• Use of surface treatment methods. Eg. Plasma treatment
Apart from the type of materials, the processing parameter has a great influence on the quality of bonding.
Some of the factors that mainly influence the bonding are:
• Melt temperatures of the two components
• The mould temperature for both components
• The cooling time of first component / delay time before injecting soft component
Materials
AKRO-PLASTIC plays an important role in modifying the materials in such a way that it achieves a good adhesion between the two components. AKRO-PLASTIC went even further by collaborating with suppliers of soft component materials to develop a complete 2K system whose materials were jointly analyzed and tested. Thus, the customer has the confidence of knowing from the start that the materials perform perfectly together.
AKROMID® A28 GF 50 1 GIT black (5029)
AKROMID® A3 GF 30 7 S3 black (5393)
AKROMID® A3 GF 40 1 L black (4671)
AKROMID® B28 GF 50 1 GIT black (4732)
AKROMID® B3 GF 30 7 L black (4912)
AKROMID® B3 GF 30 1 L black (4365)
AKROMID® B3 GF 30 2 RM-D black (3424)
AKROMID® B3 GF 50 2 RM-D black (6518)
AKROLOY® PA GF 50 natural (2916)
Testing Methods
AKRO-PLASTIC has devised its own method to test the range of adhesion-modified compounds that it develops. There are a couple of other standards like VDI 2019 and Renault Norm D41 1916 that are being widely used in the industry.
AKRO Method
• A single component injection moulding machine is used
• The hard component is injected firstly in the mould
• After 24 hours, it’s placed in the mould as an insert and the soft component is injected over it
• The 1A type tensile bars as per ISO 527 are produced
• The specimens are tested on a Universal Tensile testing machine with the hard component side fixed at the bottom and the soft component pulled at a speed of 50 mm/min.
Markets and Applications
Some of the markets or applications for which “2K” technology is being used more often are listed as below:
Automotive
• Cable channels
• Hand break grips, gear knobs
• Grab handles
• Weathering strips for doors
• Pipe connectors
• Air vent adjustment parts (thumb wheels or knobs)
• Key components
• Seal for door lock module, other housings, air vents, cowls
• Damping components
Consumer Goods and Electronics
• Electric shavers
• Wearable devices
• Mobile phone or tab components
• Seal for switch housing
Industrial
• Power tool grips
• Damping components
• Seals
Sports and Leisure
• Grips of sports Equipments
• Diving goggles
• Toys
• Luggage wheels
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